package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
@Slf4j
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {
    @Resource
    private ISeckillVoucherService seckillVoucherService;

    @Resource
    private RedisIdWorker redisIdWorker;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private RedissonClient redissonClient;

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    @PostConstruct
    private void init(){
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHanlder());
    }

    /**
     * 获取消息队列的信息
     */
    private class VoucherOrderHanlder implements  Runnable{
        String queueName = "stream.orders";
        @Override
        public void run() {
            while (true) {
                try {
                    //1.获取消息队列中的元素
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );

                    //判断获取是否成功
                    if (list == null || list.isEmpty()) {
                        //如果获取失败,则说明没有消息,继续下一次循环
                        continue;
                    }
                    //获取订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    //获取成功,可以下单
                    handleVoucherOrder(voucherOrder);
                    //ACK确认
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
                } catch (Exception e) {
                    hanldePendingList();
                    log.error("订单处理异常", e);
                }
            }
        }
        //处理pengdinglist
        private void hanldePendingList() {
            while (true) {
                try {
                    //1.获取pendinglist消息队列中的元素
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    //判断获取是否成功
                    if (list == null || list.isEmpty()) {
                        //如果获取失败,则说明pendinglist没有消息,继续下一次循环
                        break;
                    }
                    //获取订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    //获取成功,可以下单
                    handleVoucherOrder(voucherOrder);
                    //ACK确认
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
                } catch (Exception e) {
                    log.error("订单处理异常", e);
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException ex) {
                        throw new RuntimeException(ex);
                    }
                }
            }
        }
    }


    /**
     * 使用阻塞队列
     */
    /*private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);

    private class VoucherOrderHanlder implements  Runnable{
        @Override
        public void run() {
            while (true){
                try {
                    //1.获取队列中的元素
                    VoucherOrder voucherOrder = orderTasks.take();
                    //2.创建订单
                    handleVoucherOrder(voucherOrder);
                } catch (Exception e) {
                    log.error("订单处理异常",e);
                }
            }
        }
    }*/

    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        Long userId = voucherOrder.getUserId();
        //创建锁
        RLock lock = redissonClient.getLock("lock:order:" + userId);

        //获取锁
        boolean isLock = lock.tryLock();
        //判断获取锁是否成功
        if (!isLock) {
            //失败返回
            log.error("不允许重复下单");
            return;
        }
        try {
            proxy.createVoucherOrder(voucherOrder);
        } finally {
            //释放锁
            lock.unlock();
        }
    }


    /**
     * 优惠券秒杀
     * @param voucherId
     * @return
     */
    /*@Override
    public Result seckillVoucher(Long voucherId) {
        // 1.查询优惠券
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        // 2.判断秒杀是否开始
        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
            // 尚未开始
            return Result.fail("秒杀尚未开始！");
        }
        // 3.判断秒杀是否已经结束
        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
            // 尚未开始
            return Result.fail("秒杀已经结束！");
        }
        // 4.判断库存是否充足
        if (voucher.getStock() < 1) {
            // 库存不足
            return Result.fail("库存不足！");
        }


        Long userId = UserHolder.getUser().getId();

        //获取锁对象
//        SimpleRedisLock simpleRedisLock = new SimpleRedisLock(stringRedisTemplate, "order:" + userId);
        //获取锁
//        boolean isLock = simpleRedisLock.tryLock(1200);
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        boolean isLock = lock.tryLock();

        //判断是否有
        if ( !isLock ){
            return Result.fail("不允许重复下单");
        }
        try {
            //获取代理对象
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        } finally {
//            simpleRedisLock.unLock();
            lock.unlock();
        }
    }*/

    /**
     * 优惠券秒杀
     * @param voucherId
     * @return
     */

    private IVoucherOrderService proxy;

    @Override
    public Result seckillVoucher(Long voucherId) {
        //创建代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        //用户id
        Long userId = UserHolder.getUser().getId();
        //获取订单id
        long orderId = redisIdWorker.nextId("order");
        //执行Lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),userId.toString(),String.valueOf(orderId)
        );
        //判断结果
        int r = result.intValue();
        if (r != 0) {
            //没有购买资格
            return Result.fail(r == 1?"库存不足":"不能重复下单");
        }
        return Result.ok(orderId);
    }

    /**
     * 使用阻塞队列
     * @param voucherOrder
     */
    /*@Override
    public Result seckillVoucher(Long voucherId) {
        //用户id
        Long userId = UserHolder.getUser().getId();
        //执行Lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),userId.toString()
        );
        //判断结果
        int r = result.intValue();
        if (r != 0) {
            //没有购买资格
            return Result.fail(r == 1?"库存不足":"不能重复下单");
        }

        //有购买资格,把下单信息保存到阻塞队列
        //6.创建订单
        VoucherOrder voucherOrder = new VoucherOrder();
        // 6.1.订单id
        long orderId = redisIdWorker.nextId("order");
        voucherOrder.setId(orderId);
        // 6.2.用户id
        voucherOrder.setUserId(userId);
        // 6.3.代金券id
        voucherOrder.setVoucherId(voucherId);
        
        //添加到阻塞队列
        orderTasks.add(voucherOrder);

        //创建代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        return Result.ok(orderId);
    }
*/
    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        Long userId = voucherOrder.getUserId();
            //一人一单
            //查询订单
            int count = Math.toIntExact(query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count());

            //判断是否超出
            if (count > 0){
                log.error("该用户已经购买过一次");
                return;
            }

            //5，扣减库存
            boolean success = seckillVoucherService.update()
                        .setSql("stock = stock -1")
                        .eq("voucher_id", voucherOrder.getVoucherId()).gt("stock",0)
                        .update();
            if (!success) {
                log.error("库存不足");
            }
            save(voucherOrder);

    }
}


